package com.xh3140.android.widget.sliderbar;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;

import androidx.annotation.Nullable;

public class DoubleSliderBar extends AbstractSliderBar {
    // 值，必须在范围下限与上限之间
    private float mValueLower = 30F;
    private float mValueUpper = 60F;

    // 激活状态，当用户按下滑块时，处于激活状态
    private boolean mActivatedLower;
    private boolean mActivatedUpper;

    // 触摸事件
    @Nullable
    private MotionEvent mMotionEvent;

    // 进度改变监听器
    @Nullable
    private OnValueChangedListener mOnValueChangedListener;

    public interface OnValueChangedListener {
        void onValueChanged(float lower, float upper);
    }

    public DoubleSliderBar(Context context) {
        super(context);
    }

    public DoubleSliderBar(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public DoubleSliderBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public DoubleSliderBar(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // 滑块横坐标
        final float blockLowerX = mSliderStripRectF.left + v2d(mValueLower - mRangeLower);
        final float blockUpperX = mSliderStripRectF.left + v2d(mValueUpper - mRangeLower);
        // 绘制滑条(普通状态)
        mPaint.setColor(mSliderStripColor);
        if (mValueLower > mRangeLower) {
            canvas.save();
            canvas.clipRect(mSliderStripRectF.left, mSliderStripRectF.top, blockLowerX, mSliderStripRectF.bottom);
            if (mSliderStripRadius > 0) {
                canvas.drawRoundRect(mSliderStripRectF, mSliderStripRadius, mSliderStripRadius, mPaint);
            } else {
                canvas.drawRect(mSliderStripRectF, mPaint);
            }
            canvas.restore();
        }
        if (mValueUpper < mRangeUpper) {
            canvas.save();
            canvas.clipRect(blockUpperX, mSliderStripRectF.top, mSliderStripRectF.right, mSliderStripRectF.bottom);
            if (mSliderStripRadius > 0) {
                canvas.drawRoundRect(mSliderStripRectF, mSliderStripRadius, mSliderStripRadius, mPaint);
            } else {
                canvas.drawRect(mSliderStripRectF, mPaint);
            }
            canvas.restore();
        }
        // 绘制滑条(覆盖状态)
        mPaint.setColor(mSliderBlockColor);
        if (mValueLower < mValueUpper) {
            canvas.save();
            canvas.clipRect(blockLowerX, mSliderStripRectF.top, blockUpperX, mSliderStripRectF.bottom);
            if (mSliderStripRadius > 0) {
                canvas.drawRoundRect(mSliderStripRectF, mSliderStripRadius, mSliderStripRadius, mPaint);
            } else {
                canvas.drawRect(mSliderStripRectF, mPaint);
            }
            canvas.restore();
        }
        // 绘制滑块
        mPaint.setColor(mSliderBlockColor);
        if (mActivatedLower) {
            mActivatedUpper = false;
            canvas.drawCircle(blockLowerX, mSliderBlockCenter, 1.5f * mSliderBlockRadius, mPaint);
        } else {
            canvas.drawCircle(blockLowerX, mSliderBlockCenter, mSliderBlockRadius, mPaint);
        }
        if (mActivatedUpper) {
            mActivatedLower = false;
            canvas.drawCircle(blockUpperX, mSliderBlockCenter, 1.5f * mSliderBlockRadius, mPaint);
        } else {
            canvas.drawCircle(blockUpperX, mSliderBlockCenter, mSliderBlockRadius, mPaint);
        }
    }

    @Override
    public boolean performClick() {
        return super.performClick();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                final float blockLowerX = mSliderStripRectF.left + v2d(mValueLower - mRangeLower);
                final float blockUpperX = mSliderStripRectF.left + v2d(mValueUpper - mRangeLower);
                final float process = mRangeLower + d2v(event.getX() - mSliderStripRectF.left);
                if (Math.abs(event.getX() - blockLowerX) < Math.abs(event.getX() - blockUpperX)) {
                    mActivatedLower = true;
                    mActivatedUpper = false;
                    setValueLower(constraintInRange(process));
                } else {
                    mActivatedLower = false;
                    mActivatedUpper = true;
                    setValueUpper(constraintInRange(process));
                }
                mMotionEvent = MotionEvent.obtain(event);
                invalidate();
                break;
            case MotionEvent.ACTION_MOVE:
                if (mMotionEvent != null) {
                    final float distance = event.getX() - mMotionEvent.getX();
                    if (distance == 0F) return false;
                    if (mActivatedLower) {
                        mActivatedUpper = false;
                        if (distance < 0F && mValueLower <= mRangeLower) return false;
                        if (distance > 0F && mValueLower >= mRangeUpper) return false;
                        final float processLower = mValueLower + d2v(distance);
                        if (distance > 0 && processLower > mValueUpper) {
                            mActivatedLower = false;
                            mActivatedUpper = true;
                            setValues(constraintInRange(mValueUpper), constraintInRange(processLower));
                        } else {
                            setValueLower(constraintInRange(processLower));
                        }
                    }
                    if (mActivatedUpper) {
                        mActivatedLower = false;
                        if (distance < 0F && mValueUpper <= mRangeLower) return false;
                        if (distance > 0F && mValueUpper >= mRangeUpper) return false;
                        final float processUpper = mValueUpper + d2v(distance);
                        if (distance < 0 && processUpper < mValueLower) {
                            mActivatedLower = true;
                            mActivatedUpper = false;
                            setValues(constraintInRange(processUpper), constraintInRange(mValueLower));
                        } else {
                            setValueUpper(constraintInRange(processUpper));
                        }
                    }
                    if (mActivatedLower || mActivatedUpper) {
                        mMotionEvent = MotionEvent.obtain(event);
                        invalidate();
                    }
                }
                break;
            case MotionEvent.ACTION_UP:
                performClick();
                mActivatedLower = false;
                mActivatedUpper = false;
                if (mMotionEvent != null) {
                    mMotionEvent.recycle();
                    mMotionEvent = null;
                }
                invalidate();
                break;
        }
        return true;
    }

    /**
     * 获取低值
     */
    public float getValueLower() {
        return mValueLower;
    }

    /**
     * 获取高值
     */
    public float getValueUpper() {
        return mValueUpper;
    }

    /**
     * 设置低值
     *
     * @param lower 低值
     */
    public void setValueLower(float lower) {
        if (mValueLower != lower && mRangeLower <= lower && mRangeUpper >= lower) {
            mValueLower = lower;
            if (mOnValueChangedListener != null) {
                mOnValueChangedListener.onValueChanged(mValueLower, mValueUpper);
            }
            invalidate();
        }
    }

    /**
     * 设置低值，悄悄的，不会引发监听器
     *
     * @param lower 低值
     */
    public void setValueLowerQuietly(float lower) {
        if (mValueLower != lower && mRangeLower <= lower && mRangeUpper >= lower) {
            mValueLower = lower;
            invalidate();
        }
    }

    /**
     * 设置高值
     *
     * @param upper 高值
     */
    public void setValueUpper(float upper) {
        if (mValueUpper != upper && mRangeLower <= upper && mRangeUpper >= upper) {
            mValueUpper = upper;
            if (mOnValueChangedListener != null) {
                mOnValueChangedListener.onValueChanged(mValueLower, mValueUpper);
            }
            invalidate();
        }
    }

    /**
     * 设置高值，悄悄的，不会引发监听器
     *
     * @param upper 高值
     */
    public void setValueUpperQuietly(float upper) {
        if (mValueUpper != upper && mRangeLower <= upper && mRangeUpper >= upper) {
            mValueUpper = upper;
            invalidate();
        }
    }

    /**
     * 设置值
     *
     * @param lower 低进度
     * @param upper 高进度
     */
    public void setValues(float lower, float upper) {
        if (lower <= upper && mRangeLower <= lower && mRangeUpper >= upper) {
            mValueLower = lower;
            mValueUpper = upper;
            if (mOnValueChangedListener != null) {
                mOnValueChangedListener.onValueChanged(mValueLower, mValueUpper);
            }
            invalidate();
        }
    }

    /**
     * 设置值，悄悄的，不会引发监听器
     *
     * @param lower 低进度
     * @param upper 高进度
     */
    public void setValuesQuietly(float lower, float upper) {
        if (lower <= upper && mRangeLower <= lower && mRangeUpper >= upper) {
            mValueLower = lower;
            mValueUpper = upper;
            invalidate();
        }
    }

    /**
     * 设置进度改变监听器
     *
     * @param listener 监听器
     */
    public void setOnValueChangedListener(@Nullable OnValueChangedListener listener) {
        mOnValueChangedListener = listener;
    }
}
